Magnetic sound recorders



y 1 1955 E. SCHROTER MAGNETIC SOUND RECORDERS 4 Sheets-Sheet 1 OriginalFiled Feb. 10 1949 flftorae 5 July 5, 1955 E. SCHROTER MAGNETIC SOUNDRECORDERS 4 Sheets-Sheet 2 Original Filed Feb. 10, 1949 m m 3w 3 mm mm HW] mHm YEW/941624 Edward Libizi'oi'er July 5, 1955 E. SCHROTER MAGNETICSOUND RECORDERS 4 Sheets-Sheet Original Filed Feb. 10 1949 a i m 1024:90 $.92 1&9

July 5, 1955 E, SCHROTER 2,712,448

MAGNETIC SOUND RECORDERS Original Filed Feb. 10, 1949 4 Sheets-Sheet 4 sI I- V 69 215 219 7 216 475 47 un- 160 i E I E 1@ 51 j lb Edward 66727227 United States Patent MAGNETIC SOUND RECORDERS Edward Schroter,Montreal, Quebec, Canada, assignor,

by mesne assignments, to Ralph J. Samuels, Los Angeles, Calif.

Continuation of abandoned application Serial No. 75,553, February 19,1949. This application October 27, 1953, Serial No. 388,513

18 Claims. (Cl. 274-4) This invention relates to improvements inmagnetic sound recorders of the type which magnetically records soundsusually in the form of voice or music on a recording tape and plays backor reproduces the sounds recorded on the tape. This application is apure continuation application of my earlier filed application bearingSerial No. 75,553, filed February 10, 1949, allowed March 3, 1953 andabandoned November 3, 1953.

A particular object of this invention is to provide a magnetic soundrecorder with a single universal lever on a panel board for controllingthe recording and playing back of the recordings on a tape and foractuating the tape feeding and rewinding mechanisms as well as thebraking mechanism for the tape feeding and rewinding mechanisms.

Another object is to provide a novel arrangement for maintaining aconstant feed of the tape during the recording and playing back phases,the speed of which is synchronized with the sound recording andreproducing.

Another object of this invention is to provide a novel means forcooperatively actuating turntable driving mechanism and brakingmechanism as a unit to control the winding and unwinding of theturntables, when the driving mechanism is moved into and out ofengagement therewith, for maintaining tension on the tape between thereels.

A still further object of this invention is to provide a novel slip typeturntable mechanism for winding the tape at a speed consistent with itsfeed during the recording and playing back phases.

A further object is to provide means for automatically changing the sliptype turntable from recording speed to high speed winding.

A still further object is to provide a cartridge assembly upon which therecording tape is arranged for reeling and unreeling, said cartridgeassembly being removably mountable over the turntables.

A still further object is to provide an automatic control mechanism forstopping and starting the tape feed, during recording intermissions,without interrupting the power driving mechanism.

Yet another object is to provide a novel device for lineal measurementof the tape as it is fed from one reel to the other.

The above and other objects of this invention will be more readilyunderstood from the following detailed description taken in connectionwith the accompanying drawings, in which Fig. 1 is a perspective viewshowing the cabinet of a magnetic sound recorder embodying my invention.

Fig. 2 is a perspective view of the cabinet, showing the panel controlboard and the cartridge assembly raised above the turntables.

Fig. 3 is a sectional view taken along the lines 33 of Fig. 1 andshowing the apparatus in side elevation.

Fig. 4 is a top plan view, partly in section, and with certain partsbroken and the cover and cartridge assembly removed for the sake ofclarity.

i 'atented July 5, 1955 Fig. 5 is a view similar to Fig. 4, but with thecartridge assembly in place. Certain parts are broken away for clarity.

Fig. 6 is a sectional view taken along the lines 66 of Fig. 5 but withthe details in the lower compartment of the cabinet omitted for clarity.

Fig. 7 is asectional view taken along the lines 77 of Fig. 5, but withthe details in the lower compartment of the cabinet omitted.

Fig. 8 is an exploded view showing the details of the right handturntable assembly.

Fig. 9 is an enlarged view, partly broken away, of the brake andfriction driving wheel actuating mechanisms shown in Fig. 4.

Fig. 10 is a detail view of the friction driving Wheel actuatingmechanism shown in Fig. 9.

Fig. 11 is a sectional view taken along the lines 11-11 of Fig. 10.

Fig. 12 is a detail view of a lever arm actuating post shown in Fig. 3.

Fig. 13 is a view along the section line 1313 of Fig. 4 showing detailsof the magnetic eraser and its operating mechanism.

Fig. 14 is a view taken along the lines 14-14 of Fig. 6 but showing thedetails in full of the capstan clutch member as it would appear mountedabout the driving pulley collar. The clutch plate, beneath which theclutch member is arranged, is shown in dash-dot outline.

Fig. 15 is a plan detail view, partly broken away, of the dual rotarymounting of the tape measuring instruments shown in Figs. 5 and 6.

Referring more particularly to the drawings, 2 designates a housing orcabinet for a magnetic sound recorder. A supporting platform or table 3,extending across the cabinet and mounted on posts 4, generally dividesthe cabinet into upper and lower compartments. The cabinet has a coverdivided into front and rear sec tions 5 and 6. The rear section 6 ishinged to the rear of the cabinet at 7 for ready access to a removablecartridge assembly, generally indicated at 8. The front of the cabinethas a grill 9 behind which is fitted a loud speaker 10, said loudspeaker being connected to the recorder electrical equipment, generallyindicated at 11, in the lower compartment. the recorder have beenomitted for the sake of clarity since these details do not constitute apart of the present invention.

A recessed panel board 12 is arranged in the front of cabinet 2 aboveloud speaker 10. The panel board carries -a switch and tone control knob13, a volume control knob 14 and input and output sockets 15 and 16 formicrophone and earphone attachment respectively. The rearward slopingsurface of panel board 12 is provided with a vertical slot 17communicating with a horizontal slot 18 on one side thereof and withupper, intermediate, and lower horizontal slots 19, 20 and 21respectively on the other side thereof. A lever arm 22 extends throughvertical slot 17 of the sloping panel board and is selectively movableinto each of the horizontal slots. The function of the lever arm will bedescribed in detail hereinbelow. A roll top cover 23 fitted in guiderails 24 closes oi? the recessed panel board when not in use.

In Figs. 3, 4 and 6 of the drawings, I have shown a conventional motorsuspended from a plate 31 in the lower compartment. The shaft of motor30 projects through an opening in plate 31 suspended from table 3 bymembers 31a. A small diameter drive wheel 32 is mounted on the motorshaft to rotate therewith above plate 31. A friction idler wheel 33 isrotatably mounted at 34 on a tension arm 35 in a conventional manner,arm 35 is mounted for rotary and sliding movement about pin 36 carriedby plate 31. A spring 37 anchored at 38 The electrical details of toplate 31 is fastened to tension arm 35 to cause the friction wheel tobear against drive wheel 32 and a second driving wheel 39 to rotate saidsecond driving wheel in a clockwise direction about a pivotal axis pin40 carried by plate 31. Driving wheel 39 is of sufficient size and massto dampen down or tend to eliminate vibrations which might otherwisedistort the recordings.

A driving pulley is fixed to rotate with driving wheel 39 about axis pin40, pulley 45 being integrally connected to driving wheel 39 through acollar 46. Driving wheel 39 is positioned below an opening 47 in thetable 3 and pulley 45 is above the table, opening 47 being sufficientlylarge for the passage of pulley 45 therethrough. Pulley 45 has a collar50 projecting from its upper surface, said collar being recessed in thecentral portion, as indicated at 51, for the reception of a friction pad52 (see Figs. 6 and 14).

Referring particularly to Figs. 4, 6 and 14, a capstan 53, having aclutch plate 54 at the base thereof,

is mounted for free rotation about axis pin 40 with the underside of theclutch plate in contact with friction pad 52. A substantially crescentshaped clutch member 55 clutch plate 54 so that, when the capstan is inplace,

the clutch member will be arranged about collar 50. Clutch member 55 isprovided with an inwardly projecting lug 57 which normally engages in anotch 58 in the side edge of collar 50 to cause the capstan to rotatewith the pulley 45 and the integrally connected driving wheel 39. Aspring 59, fastened at one end 60 to the under side of clutch plate 54and at its other end to the free end of clutch member 55 remote from theaxis pin 56, as indicated at 61, tends to rotate the clutch member aboutpivotal axis 56 so as to engage the lug 57 in notch 58. The free end ofthe clutch member 55 is'provided with a fingerlike projection 62 whichnormally projects 7 beyond the outer periphery of clutch plate 54. 'Theclutch plate is notched as indicated at 63' at a point overlying thefingerlike projection 62 when the clutch member is in its normaloperative clutch engaging position so that the fingerlike projection 62normally serves as an obstruction at the entrance of notch 63.

An L-shaped member 65 is pivotally mounted at 66 on one side of a magnet67 secured to table 3 by screws 68. One arm 69 of member 65 is arrangedin front of the magnet head, and the other arm 70, having an inwardlydirected pawl 71, is arranged to engage pawl 71 in the notch 63 of thecapstan clutch plate 54. A spring 72, anchored at one end to table 3,and fastened at the other end to member 65, normally tends to bias themember 65 to its inoperative position by rotating member 65' pivotalaxis against the biasing spring 72. In this man-1 ner pawl 71 is broughtto bear against the edge of clutch plate 54 until it encounters thefingerlike projection 62 and then rotates the clutch member 55 about itseccentric pivotal axis 56 against the resistance of spring 59 to therebywithdraw the lug 57 from notch 58 in collar 54} to the position shown indotted lines in Fig. 14. With the eccentric arrangement .of clutchmember 55, the fingerlike projection 62 gradually recedes beneath clutchplate 54 as member 55 is rotated by pawl 71 until projection 62 isbrought up against a stop pin 74 projecting downwardly from the underside of clutch plate 54; .The stop pin 74 is positioned to allowrotation of the clutch member 55 to a point where the fingerlikeprojection 62 no longer obstructs the entrance to notch 63 in the clutchplate. Pawl 71 is thereby permitted to engage in notch 63 holding theclutch plate in the dotted line position, to prevent further rotation ofthe capstan relative to pulley 45.

When it is desired to start up the capstan, the magnet is de-energizedto release arm 69 of member 65 which is rotated to its inoperativeposition by the biasing spring 72. This action withdraws pawl 71 fromnotch 63 and from pressure engagement with the fingerlike projection 62of clutch member 55. Spring 59 thenrotates clutch member 55 about itspivotal axis 56 causing lug 57 to be brought into locking engagementwith notch 58 of the rotating collar 50.

T he motor powered driving mechanism actuates a pair or" turntables Si)and 81 through the medium of a friction driving wheel 32 fixed to rotateabout a common axis with a pulley 83 which is connected by suitable belt84 to the driving pulley 45. Turntable Si) is mounted a on a drum 35 torotate therewith. A centering pin 86 the turntable 81.

carried by table 3 serves as a common axis pin for drum 85and turntableSt). The free end of pin 86 projects beyond the upper surface ofturntable 8B for centering a tape reel thereon. A spring plate 88 issecured to the inner surface of the upper side'of turntable St? and isprovided with a locking pin 89 which projects through 21 -the turntablefor centering a second tape reel thereon.

A drum 91 is mounted for rotation about pin 99 below Drum 91 carries afriction pad 92 upon which turntable 81 rests for light frictionalengagement. Turntable 81 will rotate with drum 91 when other frictionalforces do not upset the light frictional engagement between pad 92 andthe turntable. A spring plate 93 is secured to the inner surface of theupper side'of turntable 81 and is provided with a locking pin 94 whichprojects through a hole in the turntable for locking engagement with areel when mounted on turntable 81. A plate 95 is arranged about the hub91a of disc 91 (see Figs. 3 and 7). This plate is normally supported bya shoulder 91b of the hub. One arm $6 of a lever 97 which is hingedlyconnected at 93 to table 3 is arranged below plate 95 so that the otherarm 99, when actuated, will cause arm 96 to raise and lower plate 95. Asshown in Figs. 7 and 8, drum 91 is provided with three radially arrangedholes lit-0 through which complementary pins 101 on the upper side ofplate95 are projected when the plate is raised to cause said plate torotate with the drum. The underside of turntable 81 is provided with adownwardly projecting pin Hi2 ,which is arranged in the path of rotationof pins 101 when the plate 95 is in its raised position. The nearest pin101 of the plate is brought to bear against pin 192 to provide positiverotation of the turntable with the drum.

Figs. 4 and 7 illustrate how friction driving wheel 82 and pulley 83 aremounted on a common axis pin 195 carried by one arm 196 of a crank lever1137 which is pivotally mounted on a pin 1433 carried by table 3. Aswill be seen more clearly in Figs. 9, l0 and 11, the other arm 109 ofthe lever, which isat right angles to arm 106, is provided with a pin119 which projects upwardly through an elongated slot 111 extendingtransversely of a lever actuating arm 112 overlying lever arm 1&9 andpivotally connected at one end to pin 16%. Arm iii. has a' post 113mounted thereon, by means of which the arm is rotated. Apair ofresilient pressure plates 115 are mounted on a post 156 carried byactuating arm 112. Plates 115 extend laterally-from post 116 with theirfree ends disposed on either side of pin 11%. The rotating frictiondriving wheel 82 is selectively brought to bear against the drums 85 and91 by the rotation of actuating arm 112. When the actuating arm 112 isrotated in either direction about its pivotal axis 198, one of theresilient pressure plates 115 bears against pin 111 to rotate lever 107in the same direction about the common pivotal axis 108. Slot 111 andpressure plates 115 aflord a resilient movement to the lever 107 whichprovides a cushioning eifect when contact is made between the drivingwheel 82 and either of the drums 65 or 91. Rotation of arm 112 in aclockwise direction moves friction driving wheel 82 into contact withdrum 9i and causes said drum to rotate in a counter-clockwise direction. Counter-clockwise rotation of arm 112 moves the friction drivingwheel into contact with drum 85 and imparts a counter-clockwise rotationthereto.

In Figs. 4 and 9 I have illustrated a novel braking mechanism for theturntables 80 and 81. A transverse bar 120 provided with slots 121 ismounted on posts 122 which project through said slots for lateralslidable shift ing movement of the bar. Cam riding wheels 123 and 124are rotatably mounted on bar 12%) adjacent one side edge thereof toengage cam levers 125 and 126 respectively. Cam levers 125 and 126 areeach pivotally mounted on table 3 at 127 and 128. A flexible brake arm129 has one end fastened to the pivotal end of cam lever 125 and isdisposed in side-by-side relation to lever 125 with its free end curvedaway from the free end of the lever. A brake shoe 130 on the free end ofbrake arm 129 is adapted to bear against the turntable 80. A spring 131fastened at one end to table 3 and at the other end to cam lever 125normally tends to hold the cam lever 125 against cam riding wheel 123.Lever 125 has a cam bearing projection 125:: which is fiat on its outeredge and bevelled on its flanking side edges. Similarly a flexible brakearm 132 has one end fastened to the pivotal end of cam lever 126 and isdisposed in side by side relation to lever 126 with its free end curvedaway from the free end of the brake lever. A brake shoe 133 on the freeend of brake arm 132 is adapted to bear against turntable 81. A spring134, fastened at one end to table 3 and at the other end to cam lever126, normally tends to hold the cam lever 126 against cam riding wheel124. The lever 126 is provided with cam bearing projection 126:: whichis flat on its outer edge and bevelled on its flanking side edges.

Bar 121 is provided with a cam slot 135 in which the post 113 of leveractuating arm 112 is guided for rotation of the friction driving wheellever 107 when bar 121) is shifted.

When the friction driving wheel is in its neutral position, cam ridingwheels 123 and 124 are bearing against the flat outer edges of camprojections 125a and 126a respectively causing full brake pressure ofthe shoes 130 and 133 against the turntable drums S5 and 91respectively. To rotate the turntable 81 bar 120 is shifted to the left,as illustrated in Fig. 9. The right hand offset path of cam 135 causespost 113 to rotate arm 112 which in turn rotates lever 107 in aclockwise direction, bringing friction wheel 82 into resilient contactpressure with turntable drum 91 to rotate same in a counter-clockwisedirection. During the initial shifting movement Wheel 124 rides down theinner bevelled slope of projection 126a, gradually releasing the brakingpressure on turntable 81. At the same time wheel 123 travels across theflat outer surface of cam projection 125a, maintaining the brakingpressure on turntable 86. As the brake is being released on turntable 81the friction wheel 32 is being brought into increasing contact pressurewith drum 91. While the pressure contact is being increased betweenfriction wheel 82 and drum 91 the cam bearing wheel 123 is riding downthe outer bevelled surface of cam projection 125a to thereby release thebraking pressure on turntable 80. Bar 120 is reversely shifted to centreposition causing post 113 to ride in the reverse direction in the righthand offset of cam slot 135. Post 113 causes lever 167 to be rotatedcounter-clockwise to return the friction driving wheel to neutral. Inthe initial reverse shifting stage braking pressure is first lightlyapplied to turntable by the cam wheel 123 riding up the outer bevelledsurface of cam projection a before the contact is broken betweenfriction wheel 82 and turntable 81. As the contact pressure of wheel 82on drum 91 is diminishing cam wheel-124 rides up the inner bevelledsurface of cam projection 126a to apply increasing braking pressure toturntable 81.

The reverse of the above procedure is followed to rotate turntable 81?.Bar 121) is shifted to the right causing post 113 to rotate leveractuating arm 112 through the medium of the left hand offset path of cam135. Arm 112 rotates lever 167 in a counter-clockwise direction to movefriction driving wheel 82 into resilient contact pressure with theturntable drum 35 to rotate same in a counter-clockwise direction.Braking pressure is first released on tumtable 80 followed by thereleasing of braking pressure on turntable 81 as the contact pressurebetween wheel 82 and drum 35 is made more positive. Return of thefriction driving wheel 82 to neutral is efi'ected by reversely shiftingbar 120 to the centre position which causes lever 107 to be rotatedclockwise through the medium of arm 112 which is actuated by post 113 incam slot 135. During this operation braking pressure is first applied toturntable 81 and then to turntable 80.

The bar 120 is laterally shifted by lever arm 22 which is mounted forlateral rotation at a point intermediate its length about a verticalaxis carried by table 3. Arm 22 having its outer end projectingforwardly through vertical slot 17 in the panel board 12 is providedwith an extension arm 141 having its outer end pivotally connected at142 to bar 121). The inner end of extension arm 141 overlies the innerend of arm 22 and is arranged about the vertical axis 14-3 for lateralrotation only. Arm 22 and extension arm 14-1 are fastened togetherforwardly of the vertical axis 140 by a transverse pin 143 which permitsrotation of arm 22 about a horizontal axis. The rear end of arm 22overlies the free end of the arm 99 of lever 97. When arm 22 is raisedin vertical slot 17 it depresses arm 99 to raise plate 95 through thearm 96 so that the pins 131 are projected through holes 102 in drum 91.A cover plate 144 is arranged over the brake and friction wheelmechanism and is provided with openings 144a and 14% through whichturntables 8i and 81 project.

The cartridge assembly 8 is removably mountable over the turntables 30and 81. The assembly 8 is housed in a casing 145 having a cover 146hinged to said casing at 147. A pair of tape reels 14S and 149 arearranged in the casing over openings 15:? and 151 in the bottom of thecasing. Reels 148 and 149 are retained in position by retaining walls152 and 153, or other suitable means, arranged about the outer peripheryof the reels so that when the assembly is mounted over the turntablesthe central openings 154 and 155 of the reels will receive the centeringpins 86 and 9 3 of the turntables 80 and 81. Reels 148 and 149 arebrought to bear against turntables S0 and 81 which project throughopenings 150 and 151 in the bottom of casing 145 with the placement ofthe casing on cover plate 144. Turntable locking pins 89 and 94 engagein one of the radially arranged holes 156 and 157 respectiveiy of saidreels.

A recording tape 160, which is originally wound round reel 148, istrained around a pulley mounted on a vertical axis pin 166 carried bycasing 145, in front of two spaced apart resiliently padded posts 167and 168 and then around a pressure pulley 169, with the free end of thetape secured to the reel 149. Post 167 is directly mounted on the casing145 and is positioned opposite to a magnetic eraser 170 with the tapetherebetween. Magnetic eraser 176 is mounted on an arm 171 to swingabout a horizontal axis 172 carried by table 3. The eraser 170 is showncanted away from the tape in its inoperable position (see Figs. 4, 5 and13). A spring 173 anchored at one end to a plate 174 carried by table 3has the other 7 end secured to arm 171 for biasing the eraser to itsvertical position shown in dotted lines in Fig. 13. in the verticalposition the eraser bears against tape 169, pressing the tape againstpost 167. The magnetic eraser is rotated against the biasing of spring173 by a rod 175 loosely connected at one end to arm 171 and at theother end to a crank arm 176 which is pivotaliy mounted on a verticalaxis pin 177 carried by table 3. A record listening switch 178 isconnected to the lower end of pin 177 and is act ated by the rotation ofcrank arm 176 when the eraser is moved out of contact with the tape. Theother end of crank arm 176 is connected to a second rod 179 which isprovided with a slot 13%. A supporting post 181 carried by table 3extends through slot to support the rod 179 for lateral shiftingmovement. A pin 132 on the free end of rod 171 is adapted to beprojected through a complementary opening 133 in arm 22. The arrangementof rods 175 and 179 and crank arm 176 is such that when the eraser hasbeen rotated to its inoperative position it will remain in that positionnotwithstanding the biasing of spring 173 which tends to cause theeraser to return to its vertical operating position. When rod 179 isshifted to the right by the rotation of lever arm 22 in acounterclockwise direction, crank arm 176 is rotated and releases itsrestraining pressure on the adjacent end of rod 175 so that the biasingspring 173 rotates the eraser 170 about its pivotal axis 1'72 to itsoperating position.

Resiliently padded post 168 is mounted on an arm 185 intermediate thelength of the arm. Arm 185 is mounted at one end to rotate about avertical axis pin 186 carried by the base of casing 145. A recordinghead 187 is suitably mounted on a bracket 188 which is fixed to. table3. The recording head is positioned opposite to post 168 with the tapepassingtherebetween. A spring plate 189, having one end secured at 190to casing 145, bears against post 168 to bring the tape into contactwith the recording head. The head is provided with a projection 191which is arranged over the upper edge of the tape to insure that therecording surface of the tape is positioned directly in front of therecording head.

' Pressure pulley 169 is mounted in front of capstan 53, with the tapetherebetween, to rotate about a vertical axis pin 195 carried by a leverarm 196 at a point intermediate one end and the lever arm pivotal axis197 carried by the base of casing 145. The end of lever arm 196 beyondpulley 169 engages the free end of post arrn 185 to rotate arm 135against the biasing of spring plate 139 so as to move post 168 out ofpressure contact with the tape when the apparatus is not recording. Aspring 198 having one end anchored to casing 145 and the other endsecured to the end of lever arm 196 beyond the pulley normally tends torotate said arm in a clockwise direction about its pivotal axis 197 tomove the pulley 169 away from the capstan 53 and to rotate arm 135against its biasing spring 189. A finger 199 projecting from the end oflever arm 196 and having its free end upturned pulls the tape away fromthe recording head when lever arm 196 is rotated by spring 198. A post26% mounted on casing 145 limits the rotation of the lever arm.

The other end of lever arm 196 is provided with a flexible member 261secured at 202 with its free end projecting beyond the end of the leverarm. A post 29?: mounted on lever arm 22 is adapted to bear against theprojecting end of member 2111 to rotate lever arm 196 in acounter-clockwise direction about its pivotal axis 197 to bring pressurepulley 169 into engagement with capstan 53. This action permits the post168 to impart its pressure to the tape against the recording head. Post263 is fixed to lever arm 22 for vertical movement through an opening inthe lever arm extension 141 and in a guide member 264 mounted onextension 141 to ensure vertical positioning of post 2113 at all times.When the outer end of lever arm 22 is in the intermediate or loweredpositions in slot 17 of panel 12, the post 203 will project above theupper surface of member 204 and rotation of lever arm 22 in acounter-clockwise direction causes the projecting end of post 203 tobear against the flexible projection 291 of the lever arm 196 to rotatesame. When lever arm 22 is raised above the intermediate position onpanel board 12, post 203 drops below the surface of member 204 out ofcontact with the flexible projection 2010f lever arm 196. A light spring205 is arranged about post 203 between lever arm 22 and its extension141 normally retains the outer end of arm 22 in a neutral position 1 invertical slot 17 and in alignment with the right hand horizontal siot26. The arm 22 must be raised in slot 17 to enter the horizontal slot 19or depressed against spring 205 to enter slot 21.

In the operation of the magnetic sound recorder the switch is turned onthrough knob 14 to energize motor 39 which rotates capstan 53 and theturntable friction driving wheel 82 in a clockwise direction. When it isdesired to record on the tape, lever arm 22 is depressed in slot 17 fromthe neutral position and is rotated counterclockwise to the recordingposition in the lower right hand slot 21. Bar 120 is shifted left torotate the friction driving wheel lever mechanism clockwise bringingdriving wheel 82 intoresilient contact pressure with turntable drum 91to rotate same in a counter-clockwise direction. The shifting of the baralso releases first the brake 133 on turntable 81 followed by thereleasing of brake 130 on turntable 80. This allows any slack to betaken up between the reels 148 and 149. At the same time post 293pressing against the flexible projection 291 rotates lever arm 196 in acounter-clockwise direction bringing the pressure pulley 169 to bearagainst the rotating capstan 53 with the tape therebetween and allowingpressure post 168 to press the tape against the'rnagnet head 187. As thearm 22 is depressed, pin 182 of the eraser actuating rod 179 is receivedin a hole in the arm provided therefor. The rotation of arm 22 into slot21 causes rod 179 to rotate crank arm 176 counter-clockwise, which, inturn, releases its restraining pressure on rod 175 and allows themagnetic eraser 176 to be moved to its vertical operating positionagainst the tape. In the recording position both the magnetic eraser andhead are energized.

Although friction driving wheel 82 normally tends to drive the drum 91at a comparatively high rate of speed, the tape from reel 148 is fedbetween capstan 53 and pressure pulley 169 by the rotation of thecapstan at a constant, slow rate of speed which is regulated to suit therecording on the tape. The light frictional engagement between turntable81 and drum 91 allows slipping so that the tape is only wound on reel149 as it is fed through the capstan and pressure pulley.

If it is desired to interrupt the recording without switching oi? theremainder of the mechanism, the magnet 67 is energized by suitableoutside means, for example, a press button, to trip the lever 65. Lever65 engages the crutch plate 54 of the capstan and disengages the capstanclutch from the rotating motor driven driving wheel 39 in the mannerhereinbefore described. When the magnet is tie-energized, lever 65 iswithdrawn from engagement with the clutch plate 54 permitting thecapstan to engage the motor driven mechanism to rotate therewith, in themanner previously described, and the feeding of the tape is again set inmotion.

To reverse or rewind the tape, the lever arm 22 is first moved to itsneutral position tie-energizing the magnetic eraser and head and movingthe eraser to its inoperative position by rotation of. crank arm 176 ina clockwise direction. At the same time the driving wheel82 and leverarm 196 are rotater. to their neutral positions and the brakes areapplied first to turntable 8i) and then to turntable 81 to take up theslack in the tape between the reels. Lever arm 22 is then rotated to theleft in slot 18 shifting bar 12% to the right, to rotate driving wheellever mechanism counter-clockwise and to release the brakes first onturntable 3i and then on turntable 81. Since there is a positiveconnection between drum 85 and 9 turntable the tape will be rewound onreel 148 at a high speed. It will be noted that, during this operation,finger 199 on lever arm 1% holds the tape away from the magnetic headand capstan 53.

When it is desired to play back the recording on the tape, lever arm 22is rotated counter-clockwise into the intermediate right hand slot 20.The mechanism functions the same as for recording except that themagnetic head is arranged to play back the recording and the magneticeraser is held in its inoperable position.

It is sometimes desirable to pass from one portion of the recording onthe tape to another without the necessity of playing back theintervening portion. This may be accomplished by shifting lever arm 22to neutral and then raising it in the vertical slot 17 until it can berotated counter-clockwise in the upper right hand slot 19. In thismanner bar 120 performs the same functions as for recording, but post293 being dropped below the surface of member 264, does not actuatelever arm 1% so that the tape is held away from the magnetic head andthe capstan. Similarly the magnetic eraser is retained in its inoperableposition. The raising of lever arm 22 depresses the arm 99 of lever 97to raise the plate through the medium of arm 96. The pins 191 projectingthrough openings 100 in drum 91, engage pin 1d2 of turntable 81 to givea positive high speed drive to the turntable. When the point in thereproduction of the recording has been reached the lever arm 22 isreturned to neutral and thence to the playing back position.

The tape feeding from reel 148 to reel 149 is measured on a disc 21%which is arranged beneath the cover 146 of casing to rotate about anaxis pin 211 carried by the cover. One complete revolution of disc 210represents the length of the tape and the measurements are marked on theupper surface of the disc to be viewed through an aperture 212 in cover146 of the casing as well as through a second aperture 213 in the cover6 of the cabinet. The feeding or" the tape is measured through apressure wheel 215 mounted on an axis pin 216 carried by a supportingplate 217. Pressure wheel 215 bearing against the tape as it passesaround pulley is rotated and, through a series of reduction gears,indicated at 218, rotates a second pressure wheel 219 mounted on axispin 220 carried by plate 217. Pressure wheel 219 bears against theperipheral edge of disc 21% to rotate the same. Plate 217 is pivotallymounted on the free end of an arm 221 by an axis pin 222 which has abearing member 223 arranged for movement in an elongated slot 224 intable 3. The other end of arm 221 is mounted for rotation on table 3about a pivotal axis 225. A pin 226 on arm 221 projects upwardly throughan elongated slot 277 in plate 217 to limit the rotation of plate 217relative to arm 221. A spring 223 anchored to table 3 at one end and toarm 221 at its other end, tends to rotate arm 221 so that both thewheels 215 and 219 will be in constant pressure engagement with the tapeon pulley 165 and the measuring disc 10 respectively.

I claim:

1. In a magnetic sound recorder having winding and rewinding turntablesadapted to receive the reels of a magnetic recording tape which is fedfrom one reel to the other, means mounting said turntables for rotationtherewith, a lever mounted for rotation about a pivotal axis, a motordriven friction driving wheel mounted for rotation on said leverintermediate the winding and rewinding turntables, an actuating armrotatable about said lever pivotal axis, said wheel being movable intodirect engagement with both of said turntable mounting means, meanscontinuously resiliently engaging said arm with said lever duringrotation of said lever for smooth rotation of the lever about itspivotal axis to selectively move said friction driving wheel into andout of resilient frictional rotary engagement directly with one or theother of the turntable mounting means as said actuating arm is rotated,and further means operable for rotation of said actuating arm about itspivotal axis, said last men tioned means comprising, a bar membermounted for' translational movement relative to said arm, and meansconnecting said actuating arm and bar member whereby translationalmovement of said bar member causes rotation of said actuating arm.

2. In a magnetic sound recorder having winding and rewinding turntablesadapted to receive the reels of a magnetic recording tape which is fedfrom one reel to the other, means mounting said turntables for rotationtherewith, a crank lever mounted for rotation about a pivotal axis, amotor driven friction driving wheel mounted for rotation on one arm ofsaid crank lever intermediate the winding and rewinding turntables, anactuating arm arranged to overlie the other arm of said crank lever andhaving one end mounted to rotate about the pivotal axis of said cranklever and provided at its free end with a transversely extending slot,an arm engaging pin carried by said last mentioned crank lever arm toride in said slot, flexible means mounted to resiliently engage said pinwhen the actuating arm is rotated to rotate said crank lever for movingsaid friction driving wheel into frictional rotary engagement with oneor the other of said turntable mounting means, and a further meansoperable to rotate said actuating arm.

3. A magnetic sound recorder, as set forth in claim 2, in which saidflexible means comprises a pair of resilient pressure plates mounted atone end on said actuating arm and extending laterally with their freeends disposed on either side of the arm engaging pin.

4. A magnetic sound recorder as set forth in claim 2, in which said lastmentioned means includes a bar mounted over said actuating arm andslidable relative to the actuating arm for movement in oppositedirections, said bar having a cam slot, and a post member carried bysaid actuating arm and riding in the cam slot for rotation of saidactuating arm when the bar is shifted in either direction.

5. In a magnetic sound recorder, the combination of a winding turntable,a rewinding turntable, rotatable means mounting said turntables inspaced relation to each other and for rotation with said rotatablemeans, a reel mounted for rotation on each of said turntables, arecording tape connected to said reels to be fed from one to the otherby rotation of said reels, a magnetic recording head mounted adjacentthe length of tape between said reels for recording on the tape, acapstan mounted adjacent the said length of tape, means actuating saidcapstan for predetermined constant speed rotation, a power driven rotaryfriction wheel mounted intermediate said turntables, friction wheelmounting means supported on a vertical axis for swinging said frictionwheel to selectively engage each turntable mounting means to selectivelyrotate said turntables in the same direction, braking members mountedfor separately engaging said turntables, a transverse bar mounted forlateral sliding movement in opposite directions, said bar cooperativelyengaging said braking members and said friction wheel mount ng means torotate said last mentioned means and to selectively actuate each brakingmember at predetermined intervals to control the tape feed from one reelto the other during the swinging movement of the friction wheel into andout of engagement with one or other of the rotary turntable mountingmeans, a pressure pulley engageable with one side surface of the tape, alever arm supporting said pulley and swingable about a vertical pivotalaxis to move said pulley into pressure engage ment with the tape tothereby press the tape against said capstan for regulating the feed ofthe tape in the winding direction to a speed consistent with thepredetermined speed of rotation of the capstan, a second pressure meansbiased for pressing said tape against said magnetic head and operable inresponse to movement of said lever arm to efiect pressure engagement ofsaid tape with said magnetic head, and a second le er arm mountedintermediate its length for lateral rotation in opposite directionsabout a vertical axis, said second lever arm having one end connected tosaid transverse bar for lateral sliding movement of said bar in oppositedirections in response to lateral rotation of said second lever arm, andcarried by said second lever arm for actuating rotary movement of saidfirst lever arm about its pivotal to bring said pulley into saidpressure en agement with the tape during movement of said transverse bara direction which translates rotation of said winding turntable.

6. In a magnetic sound recorder, the combination of a pair of windingand rewinding turntables adapted to receive the reels of a magneticrecording tape which is fed from one reel to the other, a driving wheelmounted between said turntables, means mounting said wheel for movingsaid wheel to selectively engage said turntables for rotation of same, abraking mechanism mounted for engaging each turntable, and a controlmember mounted for lateral sliding movement relative to said wheel mounting means and said braking mechanisms, said control member beingslidable in opposite directions to cooperatively engage said wheelmounting means and said braking mechanisms for actuating said drivingwheel and braking mechanisms to selectively control the winding andrewinding turntables at predetermined intervals when the driving wheelis moved into and out or" engagernent therewith, to maintain tension onthe tape between the reels.

7. In a magnetic sound recorder having spaced winding and rewindingturntables mounted on vertical axes and adapted to receive the reels ofa magnetic recording tape which is fed from one reel to the other, amagnetic recording head mounted at one side of the length of tapebetween reels, a rotary capstan mounted on a vertical axis at the sameside of the length of tape between said reels, a pressure pulleyengageable with the other side surface of said length of tape, a leverarm pivotally mounted intermediate its length about a vertical axis,said pressure pulley being mounted on the lever arm at one side of itsvertical axis, a spring member engaging said lever arm on the same sideof its vertical axis as the pulley mounting, said spring memberresiliently biasing said lever arm for rotation of said arrn about itspivotal axis to move the pressure pulley out of engagement with thecapstan, a finger carried by said lever arm on said one side of itsvertical axis, said finger having a part thereof disposed on said oneside of said tape adapted to move said tape away from said recordinghead when said spring member rotates said lever arm, a flexible membermounted on said lever arm at the other side of said vertical axis, andactuating means movable for engagement with said flexible member foryieldingly rotating said arm about its pivotal axis against theresilient biasing member to move the pressure pulley into engagementwith the capstan with the tape therebetween to feed the tape past themagnetic head at a constant rate of speed which is synchronized with thesound recording and reproducing.

8. In a magnetic sound recorder the combination of spaced apart windingand rewinding turntables adapted to receive the reels of a magneticrecording tape which is fed from one reel to the other past a magnetichead mounted for recording sounds on said tape, said wind= ing turntablebeing superimposed on a rotary disc about a common axis, a friction padinterposed between the turntable and disc, said pad normally providinglight frictional contact between the turntable and disc during the tapewinding operation, means mounted for frictionally engaging the disc torotate same in the winding direction to cause-said winding turntable torotate through the light frictional contact therewith, a plate mountedbeneath the disc in spaced relation thereto and movable verticallyrelative to said disc, said disc being provided with openings in itsupper surface, turntable engaging pins mounted on said plate below thesurface of said disc and aligned to project through the openings in thedisc, and a further pin carried by the turntable and projectingdownwardly therefrom into the path of rotation of the pins carried bysaid plate when the latter pins are projected through the openings ofsaid disc, and means operable for raising said plate relative to thedisc to project said plate pins through the disc openings and into thepath of said turntable pin when it is desired to provide positiverotation of said turntable in the winding direction.

9. A magnetic sound recorder including a housing, a pair of turntablesmounted in said housing for rotation about separate vertical axes, amagnetic head secured to said housing for recording on a recording tape,a power driven capstan mounted in said housing for rotation about avertical axis, and a cartridge assembly removably mounted on saidhousing over said turntables and at one side of said magnetic head andcapstan, said cartridge assembly including a base plate, a pair of reelscarried by said base plate and positioned thereon to be operably fittedon the turntables for rotation therewith when the assembly is mountedover said turntables, a recording tape trained about said reels forfeeding from one reel to the other by rotation of said turntables, andcooperative means carried by said base plate to prealign the tapeextending between said reels on the cartridge assembly for automaticpositioning of said tape adjacent the working surface of said magnetichead and said capstan as the assembly is mounted on said housing, saidmeans being operable to train the'tape extending between said reels intorecording engagement with the magnetic head and into pressure contactwith the capstan, said capstan being operable to control the feed of thetape past the magnetic head at a constant rate of speed which issynchronized with the recording;

10. A magnetic recorder, as set forth in claim 9, in which said lastmentioned means includes a lever arm mounted for rotation on said baseplate about a vertical axis intermediate the length of said arm, apressure pulley mounted on said lever arm on one side of the pivotalaxis of said arm, said pressure pulley engaging the tape and beingadapted to hold the tape in pressure contact with the rotary capstanwhen the lever arm is rotated to move said pressure pulley toward thecapstan, and means mounted on said housing to engage said lever arm onthe other side of its pivotal axis for rotating said lever arm about itspivotal axis.

11. A magnetic sound recorder, as set forth in claim 10, including apressure post pivotally mounted on said base plate for pressureengagement of the tape against the magnetic head, said post beingnormally biased to pressure engagement with the head and means carriedby the lever arm for moving said post out of pressure engagement withthe head against the resistance of the post biasing means.

12. A magnetic sound recordenas set forth in claim 9, including meansmounted for lineal measurement of the tape as it is fed from one reel tothe other, said means including a rotary indicator mounted on said baseplate and having lineal readings thereon, a wheel adapted to be rotatedby the moving tape, a second wheel adapted to rotate said indicator, agear reduction mechanism actuated by said first wheel to rotate thesecond wheel and a stabilizer supporting said first and second wheel,said stabilizer being mounted on said housing for pivotal movement tobring said first and second Wheels into pressure contact with the tapeand indicator respectively.

13. In a magnetic sound recorder the combination of spaced winding andrewinding turntables mounted for rotation about yertical axes andadapted to receive the reels of a magnetic recording tape which is fedfrom one reel to the other, a magnetic head mounted for recording onsaid tape, a rotary capstan, driving means mounting said capstan forrotation about a vertical axis for feeding the tape past the magnetichead, a clutch mechanism carried by the capstan and engageable with saiddriving means, said clutch mechanism including a clutch plate fixed torotate with said capstan at the base thereof, a clutch member pivotallyconnected for eccentric rotation to the underside of the ciutch plate,an inwardly projecting lug on said clutch member normally engaging thedriving means to rotate said capstan, means normally biasing said clutchmember to rotate said member for engaging the driving means, anoutwardly projecting member on said clutch member normally extendingbeyond the outer edge of the clutch plate when the clutch mechanism isengaging the driving means, said clutch plate being provided with anotch at the outer edge thereof and said clutch actuating mechanismcomprising a lever arm pivotally mounted for movement into and out ofcontact with the clutch plate for rotating said clutch member by itsoutwardly projecting member to disengage the clutch mechanism with thedriving means, said lever arm engaging in the clutch plate notch to stoprotation of the capstan relative to the driving means when the clutchmember has been rotated out of contact with the driving means, andfurther means operable to rotate said lever arm.

14. In a magnetic sound recorder, the combination of a pair of windingand rewinding turntables adapted to receive the reels of a magneticrecording tape which is fed from one reel to the other, a driving wheelmounted between said turntables, means mounting said wheel for movingsame to selectively engage said turntables for rotation of theturntables, brake mechanisms separately mounted for releasably engagingeach turntable, each of said brake mechanisms including a brakeactuating cam lever, a control member mounted for lateral slidingmovement relative to said wheel mounting means and said brakemechanisms, said control member being slidable in opposite directions toengage said wheel mounting means for moving said driving wheel toselectively operate each turntable, and means mounted on said controlmember and adapted to engage said cam levers for actuating said brakemechanisms to control the winding and rewinding turntables atpredetermined intervals when the driving wheel is moved into and out ofengagement therewith, to maintain tension on the tape between reels.

A magnetic sound recorder as set forth in claim 14, in which each ofsaid brake mechanism cam levers is pivotally mounted at one end to swingabout a vertical axis, and at least one of said brake mechanismsincludes a. flexible brake arm having one end fastened to the pivotalend of one cam lever and rotatable therewith, a brake shoe on the freeend of said brake arm adapted to bear against the adjacent turntable,means normally biasing said one cam lever against the cam lever engagingmeans of said control member to thereby swing said brake shoe am awayfrom said turntable, and a cam bearing projection on the free end ofsaid one cam lever, said projection having a predetermined bearingsurface contour over which said cam lever engaging means is moved duringsliding movement of said control member, to rotate said one cam leveragainst the biasing of same for the application and release of brakingpressure between the braking mechanism and the turntable, saidapplication and reie se being predetermined by the bearing surfacecontour of said cam bearing projection.

16. In a magnetic sound recorder having spaced winding and rewindingturntables mounted on vertical axes and adapted to receive the reels ofa magnetic recording tape which is fed from one reel to the other, amagnetic recording head mounted at one side of the length of tapebetween reels, a rotary capstan mounted on a vertical axis at the sameside of the length of tape between said reels, a pressure pulleyengageable with the other side surface of said length of tape, a leverarm pivotally mounted intermediate its length about a vertical axis,said pressure pulley being mounted on the lever arm at one side of itsvertical axis, a spring member biasing said lever arm for rotation ofsaid am about its pivotal axis to move the pressure'pulley out ofengagement with the capstan and actuating means movable for engagementwith said lever arm at the other side of its vertical axis for rotatingsaid arm about its pivotal axis against the resilient biasing member tomove the pressure pulley into engagement with the capstan with the tapetherebetween to feed the tape past the magnetic head at a constant rateof speed which is synchronized with the sound recording and reproducing,an arm member mounted at one end to rotate about an independent verticalaxis, a resilient pressure post carried by said arm member intermediateits length, said arm member being normally biased to bring the pressurepost into engagement with the magnetic head with the tape therebetween,said pressure pulley lever arm arranged to engage the free end of thepressure post arm to move the pressure post out of engagement with thehead when the pressure pulley is rotatably moved away from said capstan.

17. A magnetic sound recorder as set forth in claim 1 including a motorrotatably driving said friction driving wheel, a capstan engaging saidtape and being rotatably driven by said motor to feed said tape from onereel to the other at a predetermined speed, and a clutch operable torelease the drive between said motor and capstan independently of thedriving connection between said motor and friction driving wheel.

18. A magnetic sound recorder as set forth in claim 1 including a motorrotatably driving said friction driving wheel, a capstan engaging saidtape and being rotatably driven by said motor to feed said tape from onereel to the other at a predetermined speed, a clutch operable to releasethe drive connection between said motor and capstan independently of thedriving connection between said motor and friction driving wheel, andelectromagnetic means to operate said clutch.

References Cited in the file of this patent UNITED STATES PATENTS

